Vortex control for fans



Oct. 23, 1934. DOWNS 1,978,129

VORTEX CONTROL FOR FANS Filed March 14. 1932 INVENTOR ATTORNEY Patented Oct. 23, 1934 UNlTED STATES VORTEX CONTROL FOR FANS S ewell H. Downs, Kalamazoo, Mich, assignor to Clarage Fan Company, Kalamazoo, Mich.

Application March 14, 1932, Serial No. 598,785 6 Claims. (01. 230-114) The main objects of this invention are:

First, to provide anefficient adjustable means for controlling the volume of air admitted to a centrifugal fan.

Second, to provide such means that impart a swirl to the incoming air in the direction of rotation of the fan wheel.

Third, to provide such means adapted for use in handling hot ,or corrosive gases that would be injurious to controlling means within the conduit.

Fourth, to provide a suitable control device for such an apparatus.

Further objects and advantages bf the invention will appear from a consideration of the following description and the drawing, in which:

Fig. 1 is a plan view partially in section of a centrifugal fan with the invention incorporated.

Fig. 2 is an elevation partly in section taken from the right side of Fig. 1'.

Fig. 3 is a view of details of the controlling and operating means.

The parts will be identified by their numerals of reference, which are the same in all the views.

1 is a centrifugal induction fan having a casing 2 with a fan wheel 3 of conventional design supported on hearing supports 4 and 5 and having an inlet opening 6. Adjacent and opening into the inlet opening 6 is an inlet chamber 7 having an inlet- 8 thereto, and a conical deflector 9 adapted to direct the gases to the inlet opening 6 of the fan. Within the inlet casing 7 and surrounding the inlet opening 7 and the deflector 9 are a plurality of curved blades or vanes 10 journaled between ears 11 on the periphery of the inlet opening 6 andthe wall 12. of the inlet chamber 7 opposite the inlet opening 6 of the fan, as at 13.

The fan wheel 3 is mounted for rotation in counter-clockwise direction as shown by the arrow in Fig. 2. The curved blades 10 are peripherally arranged around the intake opening 6 and are so shaped that when in closed position they overlap and form substantially a cylindricalclosure means. The blades 10 are arranged that the portion of the blade in the direction of rotation of the fan is toward the center of the cylinder and overlapped by the adjacent blade.

When in partially open position the blades tend to form passages that direct the incoming air in such a manner that a swirl in the direction of the rotation of the fan is imparted to said air.

A projecting guiding portion 14 projects from the end of each-blade 10 into the intake opening 6 of the fan and. into close proximity to the fan wheel. These projections 14- are practically a ity below maximum.

continuation of the blade 10 and act when the blades are in a partially open position to practically form a substantially cylindrical flange to direct the flow of air to the center of the fan wheel, where it is easily taken up by the fan. A flange 15 is provided Within the fan casing 2 and adjacent the fan wheel to prevent back leakage of air from the fan to the inlet opening.

For control of the blades pinions 17 are provided. These pinions are mounted on rods 17 which are integral with the blades 10 and are used in the device illustrated as trunnions for mounting the blades for rotation. These rods extend outside of the inlet casing 7 and the pinions 17 are mounted on the outside of the casing. A ring gear 16 mounted for rotation on the outside of the inlet casing engages the pinions and through rotation of the ring gear all of the blades are rotated.

Although the pinions 17 are shown directly connected to the blades 10, it is obvious to anyone skilled in the art that they could be associated with these blades in any operative relationship, and it is also obvious that any other means for causing the blades to rotate simultaneously, such as a cable with suitable crank or lever connections to the blades or the rods 17', could be used.

In the drawing means for rotating the ring gear are illustrated as a lever; 18 attached to said ring gear and having a bolt 19 engaging a slot 20 of a slotted guidingquadrant 21 fastened on the wall of the inlet chamber 7 and a thumb nut 22 is provided on bolt 19 to hold the device in any desired position. a

In operation it has been found that the installation of the invention creates a considerable saving in power because there is no necessity for changing the direction of flow of the air after it enters the fan, the blades having imparted a swirl so that the air is immediately takenup by the fan wheel 3. When the device is in full open position the curved blades tend to cause a swirling of the air because of their curved nature, and in partially open position a greater swirl is imparted to the air. This has been definitely shown to efiect about 50 percent saving in the power necessary for the running of the fan at a capac- The line adjustability' obtainable by the use of this invention is desirable because by properly positioning the blades eddy currents that might ordinarily form can be eliminated through the restricting of the passages to the exact desired size.

The use of projecting guiding portions on the blades eliminates the necessity for the use 0! an inlet cone to direct the air to the center of the fan, which effects a simplification and saving in manufacturing cost.

The controlling means are especially adapted for use in conduits where hot or corrosive gases must be handled because none of the operating parts are subjected to the gases. It will be seen that the curvature of the blades on their relationship to one another to form a cylinder when closed may be varied without departing from the spirit of the invention, and it is not desired to limit the claims herein to the exact structure shown.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. In combination, a centrifugal fan, a rotatable fan wheel therefor, an inlet opening, an inlet casing adjacent said inlet opening, ears projecting from the edge of said inlet opening, a plurality of overlapping curved blades each journalled on one of said ears and on the wall of said inlet casing and adapted when in closed position to form a substantially cylindrical adjustable closure for said inlet opening with the portion of each blade that is in the direction of rotation of said fan wheel toward the inside of said closure, projecting guide portions on said blades adapted to extend into said inlet into proximity to said fan wheel to form an annular shutter within the casing to direct incoming air to said fan wheel, pinions outside of said inlet casing operatively associated with said blades, a ring gear rotatably mounted in engagement with said pinions, and means for adjusting the position of said ring gear whereby the position of the blades may be adjusted.

2. In combination, a centrifugal fan, a rotatable fan wheel therefor, an inlet opening, an inlet casing ajdacent said inlet opening, ears projecting from the edge of said inlet opening, a plurality of overlapping curved blades each journalled on one of said ears and on the wall of said inlet casing and adapted when in closed position to form a substantially cylindrical adjustable closure for said inlet opening with the portion of each blade that is in the direction of rotation of said fan wheel toward the inside of said closure, projecting guide portions on said blades adapted to extend into said inlet into proximity to said fan wheel to form an annular shutter within the casing to direct incoming air to said fan wheel, pinions operatively associated with said blades, a ring gear rotatably mounted in engagement with said pinions, and means for adjusting the position of said ring gear whereby the position of the blades may be adjusted.

3. In combination, a centrifugal fan, a rotatable fan wheel therefor, an inlet opening, an inlet casing adjacent said inlet opening, ears projecting from the edge of said inlet opening, a plurality of overlapping blades each journalled on one of said ears and on the wall of said inlet casing and adapted when in closed position to form a substantially cylindrical adjustable closure for said inlet opening with the portion of each blade that is in the direction of rotation of said fan wheel toward the inside of said closure, projecting guide portions on said blades adapted to extend into said inlet into proximity to said fan wheel to form an annular shutter within the casing to direct incoming air to said fan wheel, pinions operatively associated with said blades, a ring gear rotatably mounted in engagement with said pinions,

and means for adjusting the position of said ring gear whereby the position of the blades may be adjusted.

4. In combination, a centrifugal fan, a rotatable fan wheel therefor, an inlet opening, an inlet casing adjacent said inlet opening, ears projecting from the edge of said inlet opening, a plurality of overlapping blades each journalled on one of said ears and on the wall of said inlet casing and adapted when in closed position to form an adjustable closure for said inlet opening with the portion of each blade that is in the direction of rotation of said fan wheel toward the inside of said closure, projecting guide portions on said blades adapted to extend into said inlet into proximity to said fan wheel to form an annular shutter within the casing to direct incoming air to said fan wheel, pinions operatively associated with said blades, a ring gear rotatably mounted in engagement with said pinions, and means for adjusting the position of said ring gear whereby the position of the blades may be adjusted.

5. In combination, a centrifugal fan, a rotatable fan wheel therefor, an inlet opening, an inlet casing adjacent said inlet opening, ears projecting from the edge of said inlet opening, a plurality of rotatable curved blades, each journaled on one of said ears and on the wall of said inlet casing and adapted when in closed position to form a substantially cylindrical adjustable closure for said inlet opening and when in partially open position to impart to air entering theopening a swirl in the direction of rotation of the fan wheel, projecting guide portions on said blades extending into said inlet and into proximity to said fan wheel to form an annular shutter within the casing to direct incoming air to said fan wheel, and means operatively associated with said blades to cause simultaneous rotation of said blades and to hold said blades in adjusted position.

6. In combination, a centrifugal fan, a rotatable fan wheel therefor, an inlet opening, an inlet casing adjacent said inlet opening, a plurality of rotatable curved blades journaled around said inlet opening and adapted when in closed position to form a substantially cylindrical adjustable closure for said inlet opening and when in partially open position to impart to air entering the opening a swirl in the direction of rotation of the fan wheel, projecting guide portions on said blades extending into said inlet and into proximity to said fan wheel to form an annular shutter within the easing to direct incoming air to said fan wheel, and means operatively associated with said blades to cause simultaneous rotation of said blades and to hold said blades in adjusted position.

SEWELL H. DOWNS. 

